STRUCTURAL TESTING OF SM-2 FUEL ELEMENTS

Ability of the originally designed SM-2 stainless steel fuel elements to withstand static transverse pressure gradients of normal reactor operetion was investigated. Fourteen simulated original SM-2 type fuel elements by Tungsten inert gas (TIG) and electric resistance welding processes were subjected to pressure gradients to 6 psi and measured for deflection during stress and distortion after stress. Tests provided a basis for selecting a reference SM-2 fuel-element design and established a method of predicting maximum plate deflections under anticipated SM-2 operating conditions. Results showed that TIG welded elements, slightly more prone to deflection, are preffered for SM-2 application because they are less susceptible to weld failure and that fuel plate thickness is the most significant parameter in determining plate strength. It was also found that equilizing the length of the outer and inner plates significantly reduces maximum plate deflection and that effects of weld spacing and side plate thickness were not significant within the pressure range of the tests. (auth